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Operation Exhibit: Vehicle Performance Review

Wow, what a fun trip! Here are some things we learned (or relearned). BE SURE TO WATCH THE VIDEOS AT WWW.ZEROSOUTH.COM/GALLERY!

Packing up:

When packing up we learned several things – first, use a checklist! We spent hours running around the shop at the last minute looking for items, if we had a list it would have all been together the day before. When packing up the tracks a 6X12 trailer only works if you love back problems. So take the extra time and find an appropriate trailer (trailerplus.com maybe?). When packing up the tools, make it so that when you are roadside, they are in appropriate containers (not red bins) so that you can find what you need, and place the container in the vehicles for better access. (We placed them in the trailer and a shift in the tracks caused the roll-up door to get stuck!) Pack a bit of water, caffeine and a snack (Nick only stops for caffeine and fuel!)

Taking Off:

The first hour on the road is fairly nerve racking, so take it easy as you adjust to the steering, watching all the temps, voltages and currents. As far as estimating an ETA, a couple trips predict a simple formula, take what google says and double it – this will be fairly close with fuel stops and only minor 15-30 minute breakdowns.

The Vehicle: Experience with the sub-systems

Electric drive motors:

The electric drive motors perform very well as they are well over rated for the application. Temps never get to dangerous levels but the rear motor and inverter run a bit warmer–the stator and the rotor on the rear runs approximately 12C higher than the front motors–but still never get to high. I believe this is due to pressure drop in the cooling loop so it may not be critical to change but we should discuss it as a team). At first I though that it was because there is more weight in the rear of the vehicle however I witnessed a strange power consumption phenomenon. Nick had said that his rear system(PTV2) used more power (did more work) than the front. On the way back from SF I noticed that the FRONT did much more of the work in PTV1. I was towing the trailer and on a very slight incline doing about 55mph with the engine at 2300 RPM andconsuming about 70 KW (the front was doing about 50kw while the rear did only 20 kw). The temperatures of the Rotor, Stator and Inverter were roughly the same between the two systems, however, the front was doing most of the work. Now, for the strange part, coming back up the Grapevine during the return trip, I was doing 88kw, however the front and rear drive systems were split equally 44kw each! One of Nick’s thoughts was that the dual pots were not calibrated correctly, which could be the case and something we should look into. This seems to explain PTV2 dynamics, but not PTV1 dynamics, unless my pots were off and going up the hill transferred just enough weight to equal out the power consumption of the two systems. More experimentation is needed.

Generator:

The generator system runs fairly well and in my experience can produce 100kw constant without overheating the engine. The generator motor however will get too hot if operated over 85kw for longer than a few minutes. It seems to max out at about 100kw, I saw a couple of spikes at 108kw but seems to be regulating at about 100kw. This seems to be a limit of the engine – when coming back up the Grapevine, I was running the engine at 2600 rpm, at this RPM the torque table in the UQM inverter is limited to about 100kw. I attempted to pull more power by going up to 2900RPM on the engine, however, the engine stayed at the same RPM, so I clicked the button again under the assumption that the engine did not receive the CAN message. The engine still did not respond and the system was in a steady state condition at 100kw. At the top of the hill I let off the throttle and the Engine RPM shot up to over 3000RPM, so I quick lowered the RPM. Thus, I think that the engine may only produce 100kw – which is a bit less than it is rated for, and less than we had hoped for. This is based only on this one experience, so this may not hold true and we need more data to say for sure. The generator motor did get hot coming back up the Grapevine and I had to slow and keep power consumption to 77kw, which the generator system can produce constant and not overheat (with about 45-50F ambient temps). I was pushing the system harder than we had ever pushed it, and possibly harder than some may be comfortable with, however, I am going to be relying on this system with my life as others will, and I need to know what it can do and what the possible failure points are now while we are in a comfortable environment with plenty of equipment and support. Just past Magic Mountain, about 10 miles or so clear of the Grapevine, as the vehicle was running well, all temps had come back to normal and I was pulling around 50-66kw – I suddenly lost power. The generator stopped producing but the engine was still running. I smelled rubber and knew that the Generator Coupler had failed when the Steyr was doing 800 RPMs and the UQM Generator reported 140 RPMs. (They should always report the same RPM). I shut the engine off and pulled to the next exit on electric power, which we had done a few times. It sure is nice when the engine dies and you can pull to safety in EV mode! We pulled over and quickly diagnosed the problem as the Generator Coupler, and had to call a tow back to town by a very intimidating ex Russian captain who fought in Afghanistan. This was certainly the low point of the trip since it was midnight and so close to home. I briefly thought that we had made it, then there was failure. However, this is a great opportunity to take a look at the couplers and see how they are performing. PTV1 has about 800 more miles than PTV2, and it successfully pulled a 3000lb load for about 900 miles, so it seems logical that it would be more likely to fail than PTV2. Nick has already alerted Dan Chutes and K&N of the need be involved in a failure analysis and any necessary redesign. I am sure we will learn great things from this failure. While we were up in SF, Johnathan Knowles (our Autodesk host, and longtime friend of Nick) said, “At Autodesk, one of our mottos is fail early and fail often” – I think we do our fair share of this at ZERO SOUTH.

Wheels, Tires, Tracks:

I cannot say how much confidence it gave us to have new tires, THANK YOU RODNEY WILSON! I do not believe we would have made it with the old crappy tires that were on the vehicles. After our 3am arrival in SF, we slept for 2 hours (well I did not sure about NCB), then Todd Borgie met us at 6am and we changed both Vehicles to tracks. We picked up an electric 1/2″ impact and with an extension cord and ran it off the 120v inverter, which worked very well. The tire to track change took three people an exhausting three hours. Switching back to tires only took about an hour. We were careful to do the switch safely but we definitely need a new jack and it would be smart to devise something that raises the entire axle to the correct height for tracks or tires to reduce the switching time and increase safety. The tracks drove well, Nick had to drive PTV2 through the streets of San Francisco with just EV power steering and was still able to manage. See videos at www.zerosouth.com/gallery

Steering:

PTV1, with its mechanical Power steering (and a lot less steering slop than PTV2), steered very well on the freeway with tires and a trailer, as well as in the city on tracks. PTV2 lost it’s PS belt about 50 miles into the trip, so Nick drove on EV PS for nearly the entire trip – which was still manageable. We even drove PTV2 with EV PS and the trailer after PTV1 broke down and it was still manageable, though not as easy as PTV1, which has tighter steering as well as Mechanical PS. Upon completion of the trip, PTV1’s PS belt is showing quite a bit of wear and the white threading is showing at both edges of the belt. It did make the trip and did not lose any ribs, however, it now needs a new belt. In my opinion, we need to get the correct 3D model of our engine from Steyr and with the help of Autodesk (software and their CNC machine), build a new CNC bracket system for the PS system.

Alternators:

PTV1 Alternators worked but the belt is showing a decent amount of wear on both sides. It still has all ribs but the top of it is starting to delaminate. It could probably go another 1000 miles. PTV2’s Alt belt had been damaged from the loss of the PS belt. It had lost some ribs and we could hear them flapping around so we cut it off about 2/3 of the way to SF and ran the vehicle with the DC/DC converters turned on to charge the low-voltage batteries instead. At this point we were running the vehicle without a power steering or alternator belts so it was kind of like that scene in Apollo 13 where they had to carefully manage power (added by Nick). We turned both Blue Sea boat switches to their downward (6 o’clock) position to place the house and the crank batteries in parallel so the DC/DCs would charge both battery banks, and we turned on only necessary items and dialed down the fans to keep the low-voltage loads below the capabilities of the DC/DCs output. What’s really cool is, we proved the system could perform this way for 300 miles. In my opinion, the Alternator belt system is good enough, though it certainly would not make the production model.

DC/DC:

The DC/DC converters were able to keep the system running in PTV2 with minimal (necessary) loads turned on, however, it sagged to 12v under all the loads. They worked, however, it is my opinion that we should try to put an automotive grade DC/DC converter in the vehicle. UQM makes really nice ones, so if we could get some from them I think this would be a no- brainer, as they would hold up to any loads we could throw at them and really fortify the LV system. Here is a link: https://uqm.com/products/specialty-components/

Trailer Wiring:

The trailer wiring does not work on either vehicle. On PTV1 it’s only putting out 6 volts so we had to rig up something temporary.

Towing:

The vehicle towed very well and was stable at 55mph, where appropriate. As far as power consumption, please see the other parts of this report.

Brakes:

Coming down the Grapvine was a bit scary as the brakes overheat easily and experience brake fade quickly. We are not sure if there is much that can be done here, but we should have a discussion about it and maybe re-consider our decision to defer electric motor regen. Even though we will not need this in Antarctica, the vehicle does need to be able to travel safely here in the US. It was scary enough that I was considering trying to put the front drive system in reverse and provide some negative torque – if the situation got worse, I may have tried this, not sure if the system would do this or if it could handle this situation.

Rain:

On Friday we picked up 6 scientists from the American Geophysical Union Conference which was part of the big effort to get a corporate sponsorship from Autodesk, so needless to say, the project had a lot riding on our success. Of course it was absolutely pouring rain when we left to pickup the scientists, which was two miles away from Autodesk’s facility. Before leaving Long Beach, I had a chat with Jerry and Jim on this topic & they said that it should be ok to drive in the rain as long as the PDU, Battery Box, and inverters were sealed up. I sealed the PDU and the battery box, and tightened up the gland nuts on the inverters. I was most nervous about the rear inverter as it is in a bad spot for water. Fortunately, the vehicles did well in their first 4 miles worth of rain driving, though the under side and under hood stayed dry for the most part.

Breakdowns:

Other than the Generator Coupler failure and belt issues already mentioned, we had only a couple issues. At one point going up a hill on the freeway under boost, I heard a popping whoosh from the engine, which I had heard before and recognized. I shut down the engine which was still running and switched to EV mode and pulled off to the next exit about a 1/2 mile away. We popped the hood to find what I had expected to find – we blew off the turbo to intercooler line that was under pressure. It let go right at the turbo, so we put it back on tightened it up and were good to go. A more exciting breakdown happened on the way to SF, about halfway, I was chugging along and suddenly felt the trailer swaying out of control as though we had lost a trailer tire. I was able to calmly and safely move to the shoulder to find that the trailer had loosened itself and come off the ball, so I was dragging the trailer by the safety chains. Luckily, the trailer was equipped with a surge brake with definitely helped. Nick who was behind me said it was quite the spark show, and for several minutes until he caught up to the scene, he was sure that either a motor, inverter or the batteries had went. Since the trailer had fallen off the ball hitch, the tongue was lying directly on the ground, preventing us from getting a jack or anything under it, so we decided to test the strength of the roof rack!!! We tied a ratchet strap from the roof rack to the trailer tongue and carefully ratcheted the nearly 3000lb trailer up off the ground (only the tongue weight, though not trivial)! You can’t do that with any ol’ roof rack!! HAHA Way to design a bulletproof rack Bo Wang! We hooked it up tightened it up extra tight and had no more issues with the trailer.

Steyr ECU issue:

While transporting the scientists, Nick in PTV2, had the engine suddenly shut off and it would not restart. Later that night, we tried a few obvious things to fix the issue but to no avail. After some much needed rest I returned and found that the ECU was not powering the fuel pump as it should. I was able to fire the engine while jumping the fuel pump to +12v, however, it then died again. I checked all fuses, relays in the ECU box 12 and 24 volt sources etc… then decided to try PTV1’s ECU to start PTV2 and it worked right away. I then plugged PTV2’s ECU back in to PTV2 and it ran and worked fine for another 400 miles. We then encountered the same issue again in Valencia as I attempted to follow PTV1 – which was on the tow truck. At this point, PTV1 had permanently broke down. I called Nick, who was in the tow truck, and they pulled over so I could rob PTV1 of its ECU and ran it in PTV2 for the rest of the drive home. It seems we have a buggy ECU in PTV2, and we do not have a spare, so we will need to get one.

Radios and Communication:

We need to fix the range issue with the radios. Before we replaced the radio in PTV1, we had better range. Now it’s down to only about 30 feet! We may want to investigate another type of radio (cell based?), the VHF radios were only working if we were within 3 car lengths.

Low-Voltage System:

The Low Voltage system ran well, in PTV1 running in Hybrid mode I consume 77 amps steady state, which makes the relay fuse box quite warm. We should ensure there is no loose connections with a thermal imaging camera.

Cooling System:

Before leaving Pat, Keith and myself made a few thermal mods that made this trip possible, we installed a baffle tube inside the cool tank that lessened the turbulence in the tank, as well as put a flow restricter inline before the Thermal Cooler. This made it so that the generator was getting proper flow and only had temp issues at high loads. Nick and I agreed we can mark the thermal modification and motor overheating problems as officially “fixed.” Of course this means we did considerable driving with the systems with little or no coolant running through them which may have reduced their lifespan.

This trip really gave me so much more confidence in these vehicles. There are a few kinks to work out, but they perform just as the original team at Jay’s Garage hoped they would. They continue to impress the hell out of me, and every person that sees them is absolutely blown away. I hope other team members take the opportunity to go on public outings with the vehicles to see and feel the energy that surrounds these machines. I hope that all of you are proud of what we have worked so hard to achieve.

One thought on “Operation Exhibit: Vehicle Performance Review”

I really enjoyed reading all this information! I’ll be sure to keep coming back for updates.

I was just wondering if any thought had been given to using a manual outrigger system to keep the vehicle elevated during the tire/track swap? Nothing hydraulic or anything, just some legs that could have clevis pins put through them once the vehicle was lifted high enough. If that idea isn’t good, have you looked into using airbags to lift the vehicle?